Have you opened the drive itself up?
If this is the case, I would say that it might be some head related issue. I would say that it may be beyond repair. 🙁
Furthermore, you have opened the drive and exposed the platters to dust contaminated environment. In this case, I would say that the data may be unrecoverable as well.
In case the data is really important, you can contact the HDD manufacturer. Most of the HDD manufacturers provide data recovery services or have some data recovery partners.
D_Know_WD